The first question I would like to ask is do you smoke? If yes how many a day and since when have you been smoking?
Since you didnt mention a fever
, I think we can rule out an infection for now.
The best way to about things is to get a chest X-ray done, that way we can find out what is going on in your lungs. Another way is with with a general check up, the doctor can find out if there is any kind of consolidation in your chest. As such I recommend you go see a doctor for a general check up.
I hope this helped.